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From:   Nicolas Boichat <drinkcat@chromium.org>
Date:   Thu, 4 Feb 2021 20:34:33 +0800
Message-ID: <CANMq1KAuUTqgM2mDR5WN6Ad+cATFXLPE+5rstyhfNE9Lc716+g@mail.gmail.com>
Subject: Re: [PATCH] drm/bridge: anx7625: enable DSI EOTP
To:     Robert Foss <robert.foss@linaro.org>
Cc:     Xin Ji <xji@analogixsemi.com>,
        Nicolas Boichat <drinkcat@google.com>,
        Andrzej Hajda <a.hajda@samsung.com>,
        Neil Armstrong <narmstrong@baylibre.com>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        Jonas Karlman <jonas@kwiboo.se>,
        Jernej Skrabec <jernej.skrabec@siol.net>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Boris Brezillon <boris.brezillon@collabora.com>,
        Sam Ravnborg <sam@ravnborg.org>,
        Hsin-Yi Wang <hsinyi@chromium.org>, Torsten Duwe <duwe@lst.de>,
        Vasily Khoruzhick <anarsoul@gmail.com>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Sheng Pan <span@analogixsemi.com>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        devel@driverdev.osuosl.org
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On Thu, Feb 4, 2021 at 8:07 PM Robert Foss <robert.foss@linaro.org> wrote:
>
> Hi Xin,
>
> Thanks for the patch.
>
> On Thu, 28 Jan 2021 at 12:17, Xin Ji <xji@analogixsemi.com> wrote:
> >
> > Enable DSI EOTP feature for fixing some panel screen constance
> > shift issue.
> > Removing MIPI flag MIPI_DSI_MODE_EOT_PACKET to enable DSI EOTP.
>
> I don't think I quite understand how removing the
> MIPI_DSI_MODE_EOT_PACKET flag will cause DSI EOTP to be enabled. Could
> you extrapolate on this in the commit message?

That confused me as well, but it turns out that's how the flag is defined:
```
/* disable EoT packets in HS mode */
#define MIPI_DSI_MODE_EOT_PACKET BIT(9)
```
(https://elixir.bootlin.com/linux/latest/source/include/drm/drm_mipi_dsi.h#L129)

I'm almost tempted to put together a mass patch to rename all of these flags...

>
> >
> > Signed-off-by: Xin Ji <xji@analogixsemi.com>
> > ---
> >  drivers/gpu/drm/bridge/analogix/anx7625.c | 1 -
> >  1 file changed, 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > index 65cc059..e31eeb1b 100644
> > --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> > +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > @@ -1334,7 +1334,6 @@ static int anx7625_attach_dsi(struct anx7625_data *ctx)
> >         dsi->format = MIPI_DSI_FMT_RGB888;
> >         dsi->mode_flags = MIPI_DSI_MODE_VIDEO   |
> >                 MIPI_DSI_MODE_VIDEO_SYNC_PULSE  |
> > -               MIPI_DSI_MODE_EOT_PACKET        |
> >                 MIPI_DSI_MODE_VIDEO_HSE;
> >
> >         if (mipi_dsi_attach(dsi) < 0) {
> > --
> > 2.7.4
> >